Cerebral palsy (CP) is the most common pediatric movement disorder, affecting 3.6/1000 children in the US, with 11,000 new diagnoses every year. Motor and sensory dysfunction in CP often worsen over time, leading to costly lifelong physical, social and emotional disabilities. However, interventions that take advantage of activity-dependent brain plasticity can result in lasting improvements of movement execution and extremity use that optimize motor and social function into adulthood. Among the greatest challenges in the rehabilitation of children with CP is overcoming developmental disregard (DD). This form of neglect starts in infancy impairs the ability to infer new and effective movements and contributes to neurodevelopmental trajectories that rarely equal those of typically developing children. The sooner a therapy can overcome DD, the greater its impact on later neurodevelopment, especially if it can start before 3 years old, when neural plasticity is greatest Constraint-induced movement therapy (CIMT), well-studied in adults, improves upper extremity function through forced-use and sensory exposure of a neglected extremity. The short-term objective of this proposal is to show that CIMT at or before 2 years old can improve upper extremity sensory and motor function and thereby mitigate DD. To accomplish this, the study uses a randomized controlled trial (RCT) design with a wait- list control, in children 12-24 months with asymmetric CP. The CIMT intervention includes 1 month of soft constraint wear on the less affected arm (1/2 day sessions, electronically-monitored) combined with a validated parent-implemented home-based program of reach training and sensory exposures for the more affected extremity, in addition to routine therapy sessions (current standard CP treatment). Children with CP will be assessed at baseline, and at 1 and 7 months. Children assigned to the control group will receive CIMT after the RCT is finished and be assessed again. Typically developing (TD) age-matched children will also be tested. The RCT phase of the trial will demonstrate that CIMT improves the sensory and motor function of an affected upper extremity. The comparison of TD children and CP children before treatment will answer mechanistic questions about how the relationship between sensory and motor function contributes to impairments. Finally, referencing all CP children to TD children will provide new information on how the severity of CP and the timing of CIMT may change the neurodevelopmental trajectories of treated children. This will inform the evidence-based design of future trials of rehabilitation n developing children with disabilities. Importantly, the CIMT intervention itself does not involve extensive material and intellectual resources and focuses instead on implementing a carefully monitored home-based program, allowing an application to settings with limited access to resources. The overarching goals of this proposal are therefore to address gaps in the continuum of translational research in the field of pediatric cerebral palsy in order to increase the clinical and societal relevance of this type of rehabilitation research.